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Versions: 00 01 02 03 04 05 RFC 6232

IS-IS Working Group                                               F. Wei
Internet-Draft                                                    Y. Qin
Updates: 5304, 5310                                                Z. Li
(if approved)                                               China Mobile
Intended status: Standards Track                                   T. Li
Expires: October 21, 2010                            Cisco Systems, Inc.
                                                                 J. Dong
                                                     Huawei Technologies
                                                          April 19, 2010


             Purge Originator Identification TLV for IS-IS
                      draft-ietf-isis-purge-tlv-00

Abstract

   At present an IS-IS purge does not contain any information
   identifying the Intermediate System (IS) that generates the purge.
   This makes it difficult to locate the source IS.

   To address this issue, this document defines a TLV to be added to
   purges to record the system ID of the IS generating it.  Since normal
   LSP flooding does not change LSP contents, this TLV should propagate
   with the purge.

Status of this Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on October 21, 2010.

Copyright Notice

   Copyright (c) 2010 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal



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   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.


Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.  Requirements Language . . . . . . . . . . . . . . . . . . . . . 3
   3.  Cases to Generate Purge Packet  . . . . . . . . . . . . . . . . 3
   4.  The Purge Originator Identification TLV . . . . . . . . . . . . 4
   5.  Security Considerations . . . . . . . . . . . . . . . . . . . . 4
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4
   7.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 4
   8.  Normative References  . . . . . . . . . . . . . . . . . . . . . 5
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . . 5






























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1.  Introduction

   The IS-IS [ISO 10589] routing protocol has been widely used in large-
   scale IP networks because of its strong scalability and fast
   convergence.

   The IS-IS protocol floods purges throughout an area, regardless of
   which IS initiated the purge.  If a network operator would like to
   investigate the cause of the purge, it is difficult to determine the
   origin of the purge.  At present the IS-IS protocol has no mechanism
   to locate the originator of a purge.  To address this problem, this
   document defines a TLV to be added to purges to record the system ID
   of the IS generating the purge.


2.  Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].


3.  Cases to Generate Purge Packet

   In IS-IS there are three legitimate reasons for an IS to generate a
   purge:

   1.  An IS purges its own LSP.

   2.  A LSP owned by another IS ages out.

   3.  A new DIS is elected.

   Field experience has observed serveral other circumstances where an
   IS can improperly generate a purge:

   1.  An implementation misunderstanding [ISO 10589] or predating TC1
       generates a purge when it receives a corrupted LSP.

   2.  An implementation with bugs tries to purge one of its LSPs and
       makes a truly egregious mistake.

   3.  An implementation fails to retain the LSP header after purging
       while flooding is still in progress.







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4.  The Purge Originator Identification TLV

   This document defines a TLV to be included in purges.  This TLV
   carries the system ID of the IS generating the purge.

   This allows ISs receiving purges to log the system ID of the
   originator.  This makes it much easier for the network administrator
   to locate the origin of the purge and thus the cause of the purge.
   Similarly, this TLV is helpful to developers in lab situations.

   The Purge Originator Identification TLV is defined as:

   CODE - XX (to be assigned)

   LENGTH - total length of the value field.

   VALUE - System ID of the Intermediate System that initiated the
   purge.


5.  Security Considerations

   If the proposed TLV is used in conjunction with IS-IS authentication
   mechanisms [RFC5304][RFC5310], the purge LSP is constructed by
   removing the original contents of the LSP, leaving only the LSP
   header, adding the Purge Originator Identification TLV and then
   adding the IS-IS authentication TLV.  This document amends the
   behavior specified in [RFC5304] and [RFC5310].


6.  IANA Considerations

   RFC EDITOR NOTE: This section to be removed upon publication.

   This document requests that IANA assign a code point for this TLV
   from the IS-IS 'TLV Codepoints Registry'.


7.  Acknowledgments

   Many thanks to Adrian Farrel and Daniel King for your comments to
   improve this document and move it forward.

   The first version of this document was mainly composed by Lianyuan
   Li.

   Acknowledgments to the discussion in the mailing list.  Some
   impovements of this document are based on the discussion.



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8.  Normative References

   [ISO 10589]
              ISO, "Intermediate system to Intermediate system routeing
              information exchange protocol for use in conjunction with
              the Protocol for providing the Connectionless-mode Network
              Service (ISO 8473)", ISO/IEC 10589:2002.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC5304]  Li, T. and R. Atkinson, "IS-IS Cryptographic
              Authentication", RFC 5304, October 2008.

   [RFC5310]  Bhatia, M., Manral, V., Li, T., Atkinson, R., White, R.,
              and M. Fanto, "IS-IS Generic Cryptographic
              Authentication", RFC 5310, February 2009.


Authors' Addresses

   Fang Wei
   China Mobile
   No. 29, Financial Street, Xicheng District
   Beijing  100032
   P.R. China

   Email: weifang@chinamobile.com


   Yue Qin
   China Mobile
   No. 29, Financial Street, Xicheng District
   Beijing  100032
   P.R. China

   Email: qinyue@chinamobile.com


   Zhenqiang Li
   China Mobile
   Unit2, Dacheng Plaza, No. 28 Xuanwumenxi Ave, Xuanwu District
   Beijing  100053
   P.R. China

   Email: lizhenqiang@chinamobile.com





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   Tony Li
   Cisco Systems, Inc.
   170 W. Tasman Dr.
   San Jose, CA  95134
   USA

   Email: tony.li@tony.li


   Jie Dong
   Huawei Technologies
   KuiKe Building, No.9 Xinxi Rd., Haidian District
   Beijing  100085
   P.R. China

   Email: dongjie_dj@huawei.com



































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